Electrophysiological Correlates of Attention- and Reward-related Brain Activity in Cannabis Users: Stage II Preregistered Research Report of a Longitudinal Study

Continued drug use is thought to affect neural networks involved in attention and reward processing, with increased attentional bias being granted to drug-related versus non-drug-related cues. However, cannabis literature on this topic remains scarce, particularly longitudinal research using ERPs. This Stage II Preregistered Research Report investigated disruptions associated with cannabis (ab)use in ERP components and explored their role as potential biomarkers of future use. One hundred forty-two young adults (55 current users, 35 abstinent users, 52 nonusers, aged 18-38 years) completed a cannabis cue-reactivity task and the monetary incentive delay (MID) task during electroencephalographic data collection. We analyzed the P3, late positive potential (LPP), and reward positivity. Participants completed a 3-month follow-up on cannabis use. Compared with nonusers, current cannabis users (but not abstinent users) showed higher P3 amplitudes (when subtracting neutral cues to cannabis cues) in the cannabis cue-reactivity task. Exploratory analyses revealed that higher P3 amplitudes were associated with greater monthly cannabis use and predicted reductions in use after 3 months. In the MID task, current users showed a trend for blunted early and full-window LPP amplitudes across all monetary cues. Exploratory analysis suggested that increased LPP amplitudes to monetary loss cues and feedback, as well as blunted early LPP to non-gain feedback, may predict greater reductions in cannabis use 3 months later. As for abstinent cannabis users, they showed enhanced LPP amplitudes to cannabis versus neutral cues relative to nonusers; however, no significant group differences emerged in the MID task. These results provide exploratory evidence for a hyperactive attentional system to cannabis-related cues and a hypoactive system to other rewarding stimuli in current cannabis users; still, these effects were not uniform across ERP components or groups. In addition, this hyperactive system, revealed in components such as P3, also appears to predict reductions (vs. increases) in cannabis use over time, highlighting the complex interactions between neural activity and behavior. We discuss the findings in light of the attentional bias toward cannabis cues in current users while acknowledging alternative hypotheses that warrant examination in future research.